This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-292371, filed Sep. 26, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an X-ray image diagnosis apparatus and control method thereof which can execute contrast medium chase imaging without imposing an excessive burden of application of X-rays and injection of a contrast medium on a patient to be examined.
2. Description of the Related Art
A conventional X-ray image diagnosis apparatus for imaging a blood vessel with contrast enhanced by a contrast medium is known, which includes, for example, a substantially C-shaped support unit (to be referred to as a xe2x80x9cC-armxe2x80x9d hereinafter) and an X-ray tube serving as an X-ray source and an image intensifier (I.I.) serving as a detector which are arranged on one end and the other end of the C-arm, an image processing unit for processing acquired projection data, and the like.
Conventionally, as this X-ray image diagnosis apparatus, an apparatus having a contrast medium chase imaging function (so-called bolus-chase imaging function) is known. This contrast medium chase imaging is an imaging technique of checking, for example, the manner in which a contrast medium injected into a patient from a predetermined region flows in the patient. In the case of lower extremity imaging, for example, to check the manner in which a contrast medium injected into a patient from an abdomen as the predetermined region flows in the patient up to the ends (i.e., the tiptoes) of the two legs, this function serves to realize movement of the C-arm between these two regions and execute X-ray imaging along this movement.
In order to execute the above contrast medium chase imaging, an imaging start position and end position are checked in advance. In the above case, the imaging start position coincides with the xe2x80x9cabdomenxe2x80x9d, and the imaging end position coincides with xe2x80x9cends of the two legsxe2x80x9d (if, however, the imaging means is, for example, a so-called xe2x80x9cbolus chase DSA modexe2x80x9d, the imaging start position of a mask image may be the xe2x80x9cends of the two legsxe2x80x9d, and settings for them can be flexibly made). In addition, this imaging start position is checked on the basis of fluoroscopically sensed images.
An operator performs actual contrast medium chase imaging while manually changing the position of the C-arm at a position between the imaging start position and the imaging end position through an appropriate input means such as a jog-shuttle.
According to the above contrast medium chase imaging function described above, only imaging upon xe2x80x9cmovement in one directionxe2x80x9d from the contrast medium injection position to the direction in which the contrast medium flows can be performed. More specifically, according to the prior art, when, for example, the two legs are to be imaged, imaging of the two legs is generally executed in one direction. Assume that the contrast medium flows at different flow rates in the two legs. In this case, even if an accurate contrast medium chase can be made in one leg, the purpose of operation cannot be sometimes attained in the other leg.
For example, a reason for this is that in executing subtraction processing between an X-ray image (mask image) including no contrast medium (image) and an X-ray image (contrast or live image) including a contrast medium (image), it is difficult to simultaneously perform this subtraction processing and flexible movement of the C-arm, i.e., real-time subtraction processing.
A case where a contrast medium flows at different flow rates in the respective legs includes a case where a blood vessel (a portion) in one leg is shorter than that in the other leg, a case where a morbid portion exists in the blood vessel, and a case where some kind of anomaly is present on the inner wall of the blood vessel. In addition, the flow of a contrast medium may completely stagnate depending on the state of a morbid portion or the like (occlusion of the blood vessel).
In the prior art, therefore, in the above case, after the C-arm is moved up to the tiptoe position, or the presence of a morbid portion is recognized, a series of imaging operations must be performed from the beginning to image the other leg. According to this operation, however, the patient is exposed to X-rays twice, and a contrast medium must be injected into the patient twice, resulting an excessive burden on the patient.
In addition, the manner in which a contrast medium flows and its flow rate varies among patients to be examined regardless of whether the above morbid portion and the like exist. For these reasons, contrast medium chase imaging is basically performed manually, as described above. In general, the manner in which a contrast medium flows greatly varies among patients, and hence an operator needs to have a certain degree of skill in performing the above manual operation in order to make a successful chase.
According to the prior art, therefore, there are many cases where contrast medium chase imaging cannot be successfully done in one cycle. As a consequence, re-imaging must be done.
To perform the above re-imaging is to expose a patient to X-rays twice and inject a contrast medium into the patient twice. Such operation is not preferable.
The present invention has been made in consideration of the above situation, and has as its patient to provide an X-ray image diagnosis apparatus which can execute contrast medium chase imaging without imposing an excessive burden of exposing a patient to the examined to X-rays and injecting a contrast medium into the patient.
The present invention has the following means to solve the problems described below.
According to the first aspect of the invention, there is provided an X-ray diagnosis apparatus comprises: a bed on which a patient lies down; a support unit including an X-ray generator configured to emit X-ray to the patient and an X-ray detector configured to detect the X-ray emitted form said X-ray generator; a movement mechanism configured to change a relative position of said support unit to said the patient; a position detector configured to detect the relative position; and a memory configured to acquire an information with respect to the relative position from said position detector at timing of the X-ray emitting and store the information connected to a first X-ray image when the first X-ray image is acquired by emitting X-ray to the patient with changing the relative position in a first direction.
According to the second aspect of the invention, there is provided an X-ray diagnosis apparatus comprises: a memory configured to store a plurality of images each of which is added an information with respect to a relative position of a support unit to a patient and includes a simulated flow of a contrast medium; a image generator configured to generate a moving image, in which a contrast medium looks as if it actually flowed, by pasted the plurality of images together on the basis of the information; a display device configured to display the moving image; and an input device configured to move a field of view on the moving image in accordance with the flow of the contrast medium.
According to the third aspect of the invention, there is provided a control method of X-ray diagnosis apparatus comprises: acquiring a first image by emitting X-ray to a patient with changing a relative position of a support unit to the patient in a first direction, the support unit including an X-ray generator and an X-ray detector configured to detect X-ray emitted form said X-ray generator; acquiring an information with respect to the relative position of said support unit to said the patient at the timing of the X-ray emitting; storing the information connected to the first image; and controlling movement of said support unit on the basis of the stored information.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.